The PP motors are a strong endurance motor. The Le Mans winning engines were as were the Sebring 12 Hr winning engines. Moffats RX7s were all PPs as well. If a rotor is built correctly then they are a mighty reliable engine. My 12A has only failed me once with a twisted water seal causing a leak after a rushed reassembly.And despite that it still ran fine. Many engines are destroyed by builders who fail to understand the effect of port timing and ignition timing and end up shattering the seals though "rotor chatter" . My engine has 43 mm factory PP housings and locked 20' dizzy. With electronic injection it's good for 280HP. I can understand peoples dislike of it being in my Datto but, it has run rotarys in it longer than any piston engines so if it was to be restored which engine would you put in it?